skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Control of runaway electron energy using externally injected whistler waves

Abstract

One way of mitigating runaway damage of the plasma-facing components in a tokamak fusion reactor is by limiting the runaway electron energy under a few MeV, while not necessarily reducing the runaway current appreciably. Here in this paper, we describe a physics mechanism by which such momentum space engineering of the runaway distribution can be facilitated by externally injected high-frequency electromagnetic waves such as whistler waves. The drastic impact that wave-induced scattering can have on the runaway energy distribution is fundamentally the result of its ability to control the runaway vortex in the momentum space. The runaway vortex, which is a local circulation of runaways in momentum space, is the outcome of the competition between Coulomb collisions, synchrotron radiation damping, and runaway acceleration by the parallel electric field. By introducing a wave that resonantly interacts with runaways in a particular range of energies which is mildly relativistic, the enhanced scattering would reshape the vortex by cutting off the part that is highly relativistic. The efficiency of resonant scattering accentuates the requirement that the wave amplitude can be small so the power requirement from external wave injection is practical for the mitigation scheme.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21)
OSTI Identifier:
1471357
Alternate Identifier(s):
OSTI ID: 1423722
Report Number(s):
LA-UR-17-31490
Journal ID: ISSN 1070-664X
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 3; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Magnetic Fusion Energy; runaway electrons

Citation Formats

Guo, Zehua, McDevitt, Christopher Joseph, and Tang, Xianzhu. Control of runaway electron energy using externally injected whistler waves. United States: N. p., 2018. Web. doi:10.1063/1.5019381.
Guo, Zehua, McDevitt, Christopher Joseph, & Tang, Xianzhu. Control of runaway electron energy using externally injected whistler waves. United States. doi:10.1063/1.5019381.
Guo, Zehua, McDevitt, Christopher Joseph, and Tang, Xianzhu. Mon . "Control of runaway electron energy using externally injected whistler waves". United States. doi:10.1063/1.5019381.
@article{osti_1471357,
title = {Control of runaway electron energy using externally injected whistler waves},
author = {Guo, Zehua and McDevitt, Christopher Joseph and Tang, Xianzhu},
abstractNote = {One way of mitigating runaway damage of the plasma-facing components in a tokamak fusion reactor is by limiting the runaway electron energy under a few MeV, while not necessarily reducing the runaway current appreciably. Here in this paper, we describe a physics mechanism by which such momentum space engineering of the runaway distribution can be facilitated by externally injected high-frequency electromagnetic waves such as whistler waves. The drastic impact that wave-induced scattering can have on the runaway energy distribution is fundamentally the result of its ability to control the runaway vortex in the momentum space. The runaway vortex, which is a local circulation of runaways in momentum space, is the outcome of the competition between Coulomb collisions, synchrotron radiation damping, and runaway acceleration by the parallel electric field. By introducing a wave that resonantly interacts with runaways in a particular range of energies which is mildly relativistic, the enhanced scattering would reshape the vortex by cutting off the part that is highly relativistic. The efficiency of resonant scattering accentuates the requirement that the wave amplitude can be small so the power requirement from external wave injection is practical for the mitigation scheme.},
doi = {10.1063/1.5019381},
journal = {Physics of Plasmas},
number = 3,
volume = 25,
place = {United States},
year = {Mon Mar 05 00:00:00 EST 2018},
month = {Mon Mar 05 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on March 5, 2019
Publisher's Version of Record

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Save / Share: